import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.TreeMap;

public class TreeNode {
    /*public List<Integer> preorderTraver(TreeNode root){
        List<Integer> retlist = new ArrayList<>();
        if (root == null){
            return retlist;
        }
        retlist.add(root.val);
        List<Integer> leftTree = preorderTraver(root.left);
    }*/
    public static void main(String[] args) {
        TreeMap<String,String> map2 = new TreeMap<>();
        map2.put("及时雨","宋江");
        map2.put("国民女神","高圆圆");
        System.out.println(map2);

        HashMap<String,String> map = new HashMap<>();
        map.put("及时雨","宋江");
        map.put("国民女神","高圆圆");
        System.out.println(map);
    }



}
